Just when you think you know what's going to happen in the 138th running of the Kentucky Derby, Mother Nature throws a bit of a curveball. Although nothing is set in stone at this point, it would seem as though thunderstorms are a possibility this afternoon, and that could totally change the complexion of the race.

According to Jon Erdman of Weather.com, there were some scattered storms overnight, and while they have passed, 80-degree temperatures and high humidity are likely to lead to more storms this afternoon. There is a chance that those storms could occur in outlying counties, but the chances of at least some precipitation are pretty good.

While every trainer probably has some sort of contingency plan in case of rainfall since May is Kentucky's wettest month, it can really throw a wrench into their plans. Some horses simply can't deal with a sloppy track while others thrive on it, but the tough part for bettors is that it's difficult to know which is which.

Generally speaking, a messy track is going to play into the favor of the long shots. The top horses in terms of the betting lines are highly-touted for a reason, and that is because they have thrived in big races. The issue with that, however, is that the vast majority of those races took place in great conditions, so they may not be ready for what they'll experience in the Run for the Roses.

The 2009 Kentucky Derby is a perfect example of how a wet track can help an underdog. The conditions were awful that year and it led to one of the biggest surprises in Derby history. Mine That Bird, a 50/1 shot ridden by Calvin Borel, came from way behind in the latter stages of the race to win it all and perhaps complete the biggest upset in the illustrious history of the race.

That isn't to say that the exact same thing will happen this year if the track is in rough shape, but it simply opens up plenty of opportunities. It's going to be extremely tough for a favorite like Bodemeister, Union Rags or Gemologist to pull away because they'll have to worry about navigating through the muck.

There are a few horses who generally like to make late charges that aren't getting a lot of love from the bettors right now. The two that come to mind immediately are Daddy Nose Best, who is a 13/1 shot, and Sabercat who is currently at 33/1. While neither horse is getting much play, a sloppy track could really help them reel in the leaders down the stretch.

If you plan on putting a few bucks down on the ponies today, the weather is certainly something worth keeping an eye on. Perhaps it won't change your opinion on who you believe will win the race, but a sloppy track gives you license to take some chances and to make some riskier bets. Nobody thought Mine That Bird could win, but he used the conditions to his advantage.

There doesn't appear to be a Triple Crown-caliber horse in this race, so you shouldn't be afraid to roll the dice a little bit. Perhaps the sun will shine on Churchill Downs and all weather-related headaches will be avoided, but if the rain starts to pour then it could flip the entire field upside down.